Injector burner for autogenous metal working



July 16, 1935. A

INJECTOR BURNER FOR AUTOGENOUS METAL WORKING Filed June 2, 1934 'rl- EV Q Patented July 16, 1935 FICE.

INJECTOR BURNER FOR AUTOGENOUS METAL WORKING Felix Damm, Dusseldorf, Germany Application June2, 1934, Serial No. 728,797 In Germany January 2, 1932 .4 Claims.

This invention relates to injector burners,

more particularly for metal working, such as welding or cutting burners. Known injector burners for these'purposes have the defects that they are not economical in operation and thatthe supply of the combustible gas during working does not remain constant since, owing to the heating of the burner tip, the quantity of gas admixed is reduced. To obviate these defects, so-called high pressure or constant pressure burners have beenproposed. But even with such burners, the throttling of the combustible gas supply taking place during the working is not overcome, and no economical utilization of the mixture is attained.

The object of this invention is'to provide an injector burner in which a disadvantageous throttling of the gaseous mixture during the working is eliminated and in which the welding output is considerably increased, without additional consumption of combustible gases being necessary,

According to the invention, the improved burner is formed with a mixing chamber for the oxygen and fuel gas mixture ahead of the oxygen nozzle, which chamber communicates by means of special channels or the like with the outer air. Furthermore there is provided ahead of the first mixing chamber, a second mixingchamber with one or more hollow spaces abutting thereon which act in such manner that the 'mixture has a suction effect at the mouths of the hollow spaces. Thus,

an is-added to the fuel gas mixture inside the burner, whereby an increased economical utilization of the mixture of fuel gas and oxygen is attained, since by the replacement or" a small portion of the cylinder oxygen from the air, the out- 'let velocity, and thus the welding output of the burner, is improved without a greater consumption of fuel gases. In addition to increasing the outlet velocity, the flame cone is furthermore improved by the addition of air, this more favorably influencing. the welding output than with the use of a pure acetylene and oxygen flame. For example, in a first injector stage, fuel gas in entrained or drawn by oxygen and in a second injector stage, air is entrained by a mixture of fuel gas and oxygen. This arrangement presents the advantage that in on stage is an explosive mixture entrained, so that back-firing in the gas pipe isabsolutely avoided.

In order that the mixture may act with a suc- 7 tion effect at the mouths of the hollow spaces, a

certain partial vacuum is produced in the latter during the operation of the burner, which compensates for the throttling of the gaseous mixtureand consequently makes the supply of fuel gas uniform. V

The improved burner may also be provided with only a single mixing space which is in communication with one or more closed hollow spaces in such manner that the mixture has a suction at. the mouthpieces of the hollow spaces. This arrangement applies to burners in which merely the uniformity of the supply of fuel gas is of importance.

In the accompanying drawing:

Fig. I is a longitudinal cross-section of one construction of burner according to the invention, and

Fig.2 is a partial longitudinal section to a largerscale of a further construction of burner.

In the construction shown in Fig. 1, the oxygen, which flows out of the cylinder at a certain pressure, passes to the housing I of the burner through the pipe connection 2 into the valve 3 which can be opened and closed or regulated by by means of a handwheel 4. A conduit 5. leads from the valve 3 to an oxygen nozzle 6, from which oxygen flows into the mixing chamber 1. At this point, an injector action takes place in an annular space 8 surrounding the nozzle 6. The combustion gas passes through a pipe connection S on the housing I- into a cut-01f and regulating valve l0 which is controlled by a handwheel H, and then through a conduit l2 into an annular space l3' which is in communicationwith the annular space 8. By means of the injector action of the nozzle 6, the combustion gas also passes into the mixing chamber 1. The mixing proportion of the. two gases herein is determined by the holes inthe oxygen nozzle 6 and in an inlet nozzle Id of the mixing chamber I as also by their position in respect to each other. The mixing chamber 1 is surrounded by an annular space l5 which communi cates through holes I 6 with the outer airand through a second nozzle I! with the mixing chamher 1. From themixing chamber 1, the mixture flows through the second nozzle ll into a second mixing chamber l8. During the passage of the gas from IT to [8, an injector action again takes place in the annular space [9 surrounding the nozzle IT, by means of which atmospheric air is entrained through the holes l6 into the space I 9 and into the second mixing chamber la, in which there is now produced a mixture of oxygen, fuel gas and air. This mixture flows through a further nozzle 20 to the tip 2| of the burner, an injector action again taking place in an annular space 22 surrounding the nozzle 20, by means of which injector action a partial vacuum is constantly maintained in a second adjacent space 23., If necessary, a number of hollow spaces 23 may be provided.

If, in operation, a throttling action occurs, due to the front part of the burner being highly heated, this operates primarily on the vacuum space 23 and only to a small extent upon the nozzle 20. Here, however, the mixing proportion supplied by the injector remains constant, since the throttling can at the most only act on, the gaseous mixture and not, as with simple injector burners, on the fuel gas supply. By means of the arrangement described, an increased security against back-firing of the burner is attained since, in the first place, the ignition velocity of the mixture remains constant with the ratio of the mixture and, secondly, should for any reason backfiringnevertheless take place, this will be extinguished in the evacuated space 23 before reaching the nozzle 28. When, in consequence of very great heating of the burner tip, such considerable back pressures occur that the partial vacuum in the-subsidiary space 23 is decreased to such an extent that the back pressures act further on the rear injector stage, then both the air and the fuel gas suction injectorstages are affected. Should the partial vacuum in chambers l5 and 23 be so reduced that the back pressure throttles the oxygen from the nozzle 6 the vacuum produced by the flow from said nozzle in i3 will be likewise reduced so that even with the most highly heated burners, the ratiopof the mixture may be maintained at a constant ratio.

In the case of a welding burner having a copper tipwith a hole of 1.7. mm. and a consumption of 500 litres .per hour, the consumption for a neutrally adjusted flame is .500 litres per hour of fuel gas and 500 litres per hour of oxygen, giving a total consumption of 1000 litres per hour, which is equivalent to an outlet velocity of 119 metres per second.

, the nozzle 6 for the injector-like suction of the 75" ;Having now particularly described and ascer- With the burner according to the invention, if,

for'example, suflicient air is to be added in the second'stage to provide 10% of the oxygen, the result is that the burner in the second stage must draw in 250 litres of air per hour. The hourly consumption of the burner is consequently 500 litres of fuel gas, 450 litres of oxygen (from the cylinder), and 250 litres of air containing 50 litres of oxygen, or altogether 1200 litres of mixture, which is equivalent to an outlet velocity of 147 metres per second.

Fig. 2 shows a construction in which the supply of atmospheric air to the burner is dispensed with. With this burner also, an oxygen nozzle 6 is provided for the inlet of oxygen into the mixing chamber 1 and furthermore an annular space 8 on fuel gas out of a space [3, a second nozzle I! with an annular space l9, and a secondary space l5' or a number of such spaces abutting on to the said annular space IS. The mixture flows from the nozzle ll into the burner tube 24. Here, by the injector action at the annular space 19, a partial vacuum is maintained in the space [5 surrounding themixing space 7. Consequently,'the same action takes place as with the burner according to the first construction, the gaseous mixture remaining constant even with the greatest heating of the burner tip and flame back-firing into the suction chambers being prevented.

tained the nature of my said invention and in what manner the same is to be performed, what I claim is:

1. In a burner of the kind described, an elongated casing having a chamber therein provided at its forward end with a constricted outlet passage, a mixing chamber fitted in said casing and projecting into the first mentioned chamber, a nozzle fitted on the forward end of the mixing chamber in alinement with the constricted passage, said mixing chamber and nozzle being spaced from the wall of the casing to provide an annular chamber, a fourth chamber having a constricted port in communication with the rear end of the mixing chamber, an oxygen nozzle located in the fourth chamber in spaced relation to the wall thereof, means to supply oxygen to said nozzle, and means to supply fuel gas to the fourth chamber outside said nozzle.

2. In a burner of the kind described, an elongated casing having a chamber therein provided at its forward end with a constricted outlet pas sage, a mixing chamber fitted in said casing and projecting into the first mentioned chamber, a nozzle fitted on the forward end of the chamber in alinement with the constricted passage, said mixing chamber and nozzle being spaced from the wall of the casing to provide an annular chamber, a fourth chamber having a. constricted port in communication with the rear end of the mixing chamber, an oxygen nozzle located in the fourth chamber in spaced relation to the wall thereof, means to supply oxygen to said nozzle, and means to supply fuel gas to the fourth chamber outside said nozzle, said casing having air ports therein opening into the space around said first nozzle whereby to admit air thereto.

3. In a burner of the kind described, an elongated casing having a chamber therein provided at its forward end with a constricted outlet passage, a mixing chamber fitted in said casing and. projecting into the first mentioned chamber, a

nozzle fitted on the forward end of'the mixing.

chamber in alinement with the constricted passage, said mixing chamber and nozzle being spaced from the wall of the casing to provide an annular chamber, a fourth chamber having a constricted port in communication'with the rear end of the mixing chamber, an oxygen nozzle located in the fourth chamber in spaced relation to the wall thereof, means to supply oxygen to said nozzle,

means to supply fuel gas to the fourth chamber outside said nozzle, said fourth chamber constituting a primary mixing chamber for fuel and oxygen, said casing having air ports therein opening into the space around said first nozzle whereby to admit air thereto, a third mixing chamber located in the forward part of the casing and leading from said constricted passage, a nozzle fitted on the forward end of said third mixing chamber, said last mixing chamber and nozzle being spaced from the wall of the casing to provide an annular vacuum chamber, said casing having a constricted passage at its forward end, and a burner tip in communication with the last mentioned constricted passage.

; 4. In a burner of the kind described, an elongated casing having a chamber therein provided at its forward end with a constricted outlet passage, a mixing chamber fitted in said casing and projecting into the first mentioned chamber, a nozzle fitted on the forward end of the mixing chamber in alinement with the constricted passage, said mixing chamber and nozzle being spaced from the wall of the casing to provide chamber outside said nozzle, said mixing chamber having the space therein increasing in area from the inlet end to the outlet end and the nozzle of said mixing chamber having its bore decreasing from its inlet to its outlet.

FELIX DAMM. 

